Free piston engine pendulum pump



May 12, 1964 E. A. KARIBA ETAL FREE PIsToN ENGINE PENDULUM PUMP 4 Sheets-Shea?l 1 Filed Aug. 17, 1961 am W TWA L. N

JE@ M OM May 12, 1964 E. A. KARIBA ETAL 3,132,593

FREE PIsToN ENGINE PENDULUM PUMP Filed Aug. 17, 1961 4 sheets-sheet s l IN VEAN-0K5 ED w/'Jv JQQE/A pQc/L X50 LTL/off PME/L M@ May 12, 1954 E. A. KARIBA ETAI. 3,132,593

FREE PIsToN ENGINE PENDULUM PUMP Filed Aug. 17, 1961 4 sheds-sheet 4 FEDA/l 1 anp TN 1/ EN To E s Bbw/NA )@QPJZQA' United States Patent O M2593 FREE Pllflllsl Eltlt'lililil PENDULUM PUMP Edwin A. Karina, Clticagmand C. liaui Kolthoil, Sr., Naperville, Ill., assignors to International Harvester Company, Chicago, lll., corporation or' `Itslew Jersey Filed Ang. ll, llltill, dal'. No. 1.32,@5@

9 Claims. l-Cl. lullin-5d) This invention relates to a single cylinder free piston engine wherein the reaction of the piston moving in one direction is compensated` by movement of the engine block in the other direction in balanced relation thereby minimizing or eliminating vibratory forces on` the engine support. More in particular this invention relates to a dynamically balanced single cylinder free piston engine having minimal vibratory stress on the support means therefor.

In the past, single cylinder reciprocating piston internal combustion engines oi the free `piston type have their `blocks supported in stationary relation-` Thus reactive forces occurring` during piston movement must be absorbed by the engine and `its support which necessitated strong mounting means to` accommodate these vibratory shock forces. The present invention contemplates overcoming this problem oy providing` a movable engine block which always moves in a direction opposite to the movement of the piston. Now if the effective mass of the engine block is substantially equal to the effective mass of the piston then a full stroke of the piston relative to the bloclc actually moves only one-half of afull stroke with respect to the stationary engine mounting, the other onehalf stroke being the movement oi the block inthe opposite direction.

The term eli ctive mass as employed herein is intended to mean the total weightincludmg all components which reciprocate together including an amount to compensate for friction.

The utility of the engine of this invention may be that of a gasiiier for driving a turbine. However, this invention also contemplates deriving worlr from the engine by incorporating a iiuid pump, such asa hydraulic pump, within the engine structure.

lt is therefore a prime object of this invention to provide a single cylinder free piston engine wherein the engine block nieves in one direction substantially equal to the distance the piston moves in the other direction.

Another object of this invention is to provide a single cylinder free piston er gine wherein the support means for the engine is substantially free from vibra ing stresses during operation.

Still another object of this invention is to provide a free piston engine according to the preceding objects wherein the engine has an `internally constructed duid pump.

f Yet another object; of this invention is to provide a startin.c means for the free piston engine according to the preceding objects.

These and other` important objects inherent in and encompassed by the invention will be more readily understood from the ensuing description, the appended claims and the annexed drawings wherein:

FIGURE l is a vertical crosssection View taken along the longitudinal axis oi the free piston engine pump of this invention.

FIGURE 2 is a transverse cross-section view taken along the line 2 2 of FlGURE l illustrating the arrangement of the check valves for the engines air compressor.

FIGURE 3 is a transverse cross-section View with power piston and head removed talten along the line 3 3 of FIGURE 1 showing a portion of the engine block with its cylinder` sleeve or liner.

. gine iiuid pump of this invention.

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With continued reference to the drawings in FIGURE l the numeral lill indicates generally the freer piston en- The engine lll comprises a block member which for manufacturing and assemblingreasons comprises a cylinder head lll, an upper casing l2 and a lower casing i3 rigidly connected together as by bolts, three of which are shown at ld, l5 and lo. The block member ll, l2 and lill, isI preferably made of a low specic gravity material such as,` for eX- ample, aluminum alloy.

The block member ll, l2 and i3, is provided with conventional ns i7 to facilitate disposition of heat which avoids the necessity of increasing its mass by providing a conventional liquid coolant jacket. i Y The block member ll, l2 and i3 may be provided with a conventional wear resistant sleeve or cylinder liner le? to facilitate slidable movement of a power piston assembly generally indicated at 19.

The engine ll@ is provided with a combustion chamber 2li, an air compressor chamber 2l and a resilient reaction chamber 22 commonly referred to as the oounce chamber. The power piston i9 includes, as a portion thereof, a large piston or compressor piston 23. The

. bounce chamber 22 of this device operates for only a portion of the compressor piston stroke as it is Vented to the atmosphere when the compressor piston Z3 uncovers the port Z2 in the lower casing i3. This provides an initial atmospheric bounce pressure for each operating cycle. If the port 22 was omitted, the initial bounce pressure could fluctuate, depending on leakage from or to the bounce chamber 22. The `block member lll, 12 and I3 is provided with at least one air inlet check valve 2d and at least one air outlet check valve 25. The check valve 2d permits air tochter from the atmosphere (or extern nal supercharger) into the compressor chamber 2l during the intake stroke of the compressor piston 23. The

check valve 25 permits air from the compressor chamber 2l to discharge under pressure into the air box 26 during the compression stroke of the compressor piston Air inlet ports 27 communicate compressed air from the air box 26 into the combustion chamber 2d' through the cylinder liner idas shown in FIGURES 1 and 3. Exhaust ports 2S are also provided for discharging the products of combustion from the chamber 2d through the cylinder liner i8 and upper casing l2 into conduct Zi? as shown. The ports Z7 and 28 are valved by movement of the power piston li) as is conventional in loop scavenged two-cycle engines. l

Referring now to FIGURES 1 and Z it Will be seen that the air check valves 24 and 25 as shown comprise a plurality of conventional reed type valves. Thus` as shown a total of twentyfour reed valves comprise the air inlet check Valve 24 and an equal number comprise the air outlet check valve 25. Reed type valves are preferable as they are of 10W mass and quite sensitive to a reversal of differential pressure of low magnitude.

The cylinder head 11 is provided with a conventional fuel injector, indicated at 30, which injects a metered aisance quantity (selectively variable) of fuel into the combustion chamber 20 when the pressure in the chamber Ztl elevates beyond a predetermined value. Subsequently when the pressurein chamber 20 is reduced below a predetermined pressure the fuel injector automatically resets itself preparatory to the next fuel injection cycle. Numerous types of fuel injecting mechanisms of this type are known, one of which is described in U.S, Patent No. 2,799,263 to Louis O. French.

Slidably disposed in the cylinder liner 18 is the power piston 19 which may hev provided with conventional sealing rings, three of which are shown at 31. Likewise the compressor piston 23 portion of the power piston assembly 19 may also be provided with conventional sealing rings three of which are shown at 32. As indicated the compressor piston 23 is in slidable relation with an internal bore 33 disposed within the lower casing 13 of the block member.

Rigidly secured in stationary relation is a support member, generally indicated at 34, for the engine 10. The support member 34 may conveniently be secured to a rigid foundation, a fragmentary portion indicated at 35 in FIGURE 1, as by bolts, two of which are shown at 36 and 37. The support member 34 comprises a base plate 38 rigidly connected to a stationary huid pump cylinder 39 extending perpendicularly therefrom as shown in FIGURE 1.

Referring to FIGURE it will be seen that the pump cylinder 39 is provided with an elongated slot 4i? extending longitudinally a distance somewhat greater than one-half the maximum stroke of the power piston 19 relative to the block member 11, 12 and 13. The longitudinally extending sides of the slot 4t) are defined by the walls 41 and 42 as best shown in FIGURE 5.

Disposed in longitudinally movable relation within the slot 40 in the pump cylinder 39 is a transverse bracket 43 the end portions of which are secured to the lower end of the block member as by bolts 44 and 45. Thus as the lower casing 13 of the block member reciprocates in slidable relation with the outer surface 46 of the pump cylinder 39, the bracket 43 reciprocates in the slot 49.

Connected in longitudinal drive relation to the bracket 43 is a lower pump piston 47. The pump piston 47 is in slidable relation within a longitudinally extending bore 48 disposed within the stationary pump cylinder 39 as best shown in FIGURE 1. The pump piston 47 is connected to the bracket 43 by a conventional ball and socket linkage, generally indicated at 49, which compensates for Iany misalignrnent between the bore 48 and the outer surface 46 of the uid pump cylinder 39 due to manufacturing tolerances. Thus it can be seen that the lower pump piston 47 moves reciprocatingly with the block member 11, 12 and I3.

Within the bore 48 of the pump cylinder 39 in opposed relation with the lower pump piston 47 is an upper pump piston 50 connected to the power piston assembly 19 for longitudinal movement therewith. The power piston assembly 19 includes a bracket 51 connected to the piston 19 as by bolts, two of which are shown at 52 and 53. The connection between the bracket 51 and the upper pump piston 50 is by means of a conventional ball and socket linkage indicated at 54 which allows some transverse movement of the pump piston 5t) with respect to the power piston 19. This prevents binding of the pump piston 50 with the bore 48 by reason of slight misalignment due to manufacturing tolerances. Thus the upper pump piston 5t) reciprocates with and is part of the power piston assembly 19.

The pump cylinder 39 is provided with a longitudinal bore 119 shown in dotted lines in FIGURE 1 is provided for venting to the atmosphere the space 121i so that it does not function as an auxiliary bounce chamber which otherwise might create unwanted forces. Further it serves to assist in cooling the underside of the piston 19.

Between the inner face 55 of the upper pump piston 50 and the inner face 56 of the lower pump piston. 47 in the bore 48 is a fluid pump chamber 57. Referring now to FIGURES 1, 4 and 5 it will be seen that the stationary Huid pump cylinder 39 is provided with two longitudinal fluid conducting bores, one being a fiuid inlet bore 53 and the other being a iluid outlet bore 59, both bores being in parallel spaced relation and extending through the base plate 33. The inlet bore 58 is connected to a source of low pressure iiuid such 'as a reservoir or accumulator 69 through a conventional inlet check valve 61 as indicated in FIGURE 7. Similarly the outlet bore 59 communicates with a high pressure accumulator or other fluid pressure receiving device 62 through an outlet check valve 63 indicated also in FIGURE 7.

Referring to FIGURE 4 it will be seen that the fluid inlet bore 58 communicates with the pump chamber 57 through transverse bore 53 and the fluid outlet bore 59 communicates with the pump chamber 57 through transverse bore 59 as shown.

Although the engine pump 19 is capable of being started by conventional means a novel starting system particularly adapted for the engine pump it) is shown schematically in FIGURE 7.

Referring to FEGURE 7 the letter M represents a hydraulic motor preferably of the rotatable type such as a gear motor. The hydraulic motor M drives a hydraulic pump P, preferably of the rotatable type such as a gear pump, mechanically through linkage indicated at 64. Thus when the motor M is energized it drives the pump P mechanically.

The numeral 65 indicates a iiuid metering unit comprising a metering cylinder 66 having a metering piston 67 slidably disposed therein. The volume below the piston 67 is termed the metering chamber 68 yand the volume above the piston 67 is termed the actuating chamber 69. When the piston 67 is in the position shown in full lines the actuating chamber 69 is of large volume while that of the metering chamber 63 is approaching zero. On the other hand when the position of piston 67 is in the position 67 as shown in dotted lines the reverse is true.

The starting system is provided with a fluid sump 7th and a start valve indicated at 71. The start valve 71 is a spool type valve comprising a housing 72 having a bore 73 therein. Slidably disposed within the bore 73 is a spool valve member indicated at 74. The valve member or plunger 74 comprises a pair of lands 75 and 76 separated longitudinally by a circumferential groove 77. The land 75 is positioned in registerable relation with port 7S and land 76 is positioned in registerable relation with port 79. A third port 8@ is positioned for registration with circumferential groove 77. A compression spring 31 is positioned as shown for urging the plunger 74 rightwardly toward the position indicated in dotted lines. Within the bore 73 rightwardly of the plunger 74 is a valve chamber 82'in communication with conduit through connecting conduits 33, 34. Thus when the valve chamber 82 is energized the plunger 74 moves leftwardly to the position shown in full lines and when the chamber 82 is de-energized the plunger 74 moves rightwardly to the position shown in dotted lines due to the action of spring 31.

lIhe outlet side of the hydraulic motor M communicates with the sump 7i) through conduits 85 and 36 while the discharge side of pump P communicates with the sump 7@ through conduits SS and E7 as shown. The inlet side of pump P communicates with the pump chamber 57 of the engine 1@ through conduit 88, normally closed manually operated valve 191 and conduit 59. A vacuum limiting bypass for conduit 33 is provided for the pump P through conduit 89 and relief valve 96 as indicated. The inlet side of the motor M communicates with the actuating chamber 69 of the metering unit 65 through conduits 91 and 92. A normally closed manually operated valve 93 is interposed in the conduit 91 as shown.

T he actuating chamber 69 of the metering unit 65 communicates with the high. pressure fluid accumulator 62 through conduits 92 and dit. A normally open manually operated valve 95 is interposed in the conduit 92?, as indicated. IInterposed in the conduits 94 to itil as shown is a normallyrclosed manually operated valve 9d.

The conduit 9d also communicates with the metering chamber 6h of the metering unit d through conduits 97 andb as indicated in liiGUEtE 7. rllhe port 'll of the start valve '7l communicates with the conduit @through connecting conduit 99 as shown. Amanually operable start control valve 7l is `interposed between conduits 9dr and 83 as shown. Lastly, interposed in the conduit 5d is a normally open manually operated valve lith.

Having described construction of the engine pump u it can readily be appreciated. that the fluid pump pistons d7- and Si) may come to rest `at most any position of their respective strokes. The starting system requires that the pump pistons i7 and dit must irst be brought to their maximum inboard position as illustrated in FEGURE l. Thereafter a metered charge of high pressure hydraulic iluid is introduced into the pump chamber 57 which drives the pump pistons t7 andS-"Zl outwardly in opposite directions. This has the ecect of driving the pov/cr piston lll on its fuel-air compression stroke with respect to the movable block member `ll, l2 and i3. As soon as the compression pressure in the combustion chamber rises to a predetermined value, the pressure actuates the fuel injector 30 whereby a metered charge of fuel is injected into the combustion chamber Ztl. Compression in the combustion chamber itil continues to rise at the urging of the initially created inertia of movement even `without further urging of fluid pressure in the pump chamber 57 until combustion occurs through compreasien-ignition. The power piston ,1 9 thereafter is driven downwardly and the reaction force against the head lli` drives the block member dll, l2 and .i3 upwardly. 'However since the effective mass of the power pistou assembly i9 including itsassociated members aggregately is substantially equal to the effective mass o the block member il, l2 and i3 including its associated elements, the distance that the powerpiston l@ moves downwardly with respect to the stationary support member 3d will be substantially equal tothe distance the bloeit member ll, l2 and i3 moves upwardly. The power stroke thus compresses the in the bounce chamber 22 which reacts to move the power piston 19 a-nd the block member in the opposite direction thereby initiating the next` compression-.ignition cycle, On` succeeding cycles there is no metered charge of high pressure hydraulic lluid for then the pump chamber 57 isv filled by low pressure oil from accumulator ntl.

Starting Referring to FlGURE 7 the high pressure fluid accumir lator 62 must be charged under pressure. Assuming no iiuid :leakage the accumulator dit will be charged from the previous operation of the engine pump ltl. p Otherwise the accumulator e2 must first be charged from an external source.

Step one: Close all normally open valves. `In other words close valves li and idf).

Step two: Open normally closed valves h3, lill and "71. This permits hydraulic fluid in valve chamber S2 to escape through port titl and conduit 99 so that spool valve member 74 may moveto the position indicated by the dottedlines as urged by the spring Step three: Close the start control valve 7l.

Step four: Open the normally closed valve 96.' This permits the fluid pressure from the high pressure accumulator 62 to pass through conduit 9d, open valve 96, conn duit 94', conduits 9] and 98 to pi'essurize metering chamber 68 of the fluid metering unit 65. Pressurizing the metering chamber 65 now urges the metering piston 67 upwardly thereby also pressurizing the actuating chamber 69. Pressurizing the actuating chamber 69 discharges the tluid therein through conduit 92, opened valve 53 and conduit @l to the inlet side of motor M. The discharge trom the motor M passes to the sump 7 il through conduits and d5. The hydraulic motor M is thus energized to drive the pump P in a direction for evacuation of fluid from the pump chamber 57 of the engine pump lll. lIt will be noted that the valve @d is closed during this step so that the metering piston 67 will be urged upwardly to the position shown at 6'7".v Since the pump P is still being driven by the motor M and the valve lltlil is closed the pump chamber S7 of the engine pump it? will be under sub-atmospheric pressure which draws pump pistons 4,7 and 5d toward ltheir respective inboard positions and the evacuated uid from the pump chamber S7 is delivered to the sump 7d through conduits 59', opened valve itil, conduit lid, pump P, and conduits S7 and 35. When the pump pistons i7 and 5d have reached their respective inboard positions as shown in FIGURE l, and the metering piston e7 has been elevated to its upper limit the system is ready for the next step. An inlet check valve litt manually openable` for reverse iluid ilow` is provided on the lower casing i3 of the block member to exhaust the bounce chamber for facilitating inboard movement of the power piston with respect to the block member.

Step five: Close all of the previously opened normally closed valves. `ln othe Words close valves 93, @n and This step has the effect of terminating further discharge from the high pressure accumulator 62 and thus the hydraulic motor M becomes deenergized thereby terminating operation of the pump P. However the metering piston 67 will remain elevated because the spool Valve member 'Tl will still remain in its rightward position,

` shown in dotted lines in FlGURE 7, and valves 7l and 9o are in closed position. iThus fluid in the metering chamber ab is under fluid lock.

Step sin: `Open all of the previously closed normally open valves. In other words open valves and lill). Opening of the valve 95 has not effect except to pressurize the actuating chamber o@ which of course urges the metering piston 67 downwardly. However, the metering piston ti does not move downwardly `because the fluid in the metering chamber 6l? is under hydraulic lock as previously explained but of course the fluid in chamber dil is'now pressurized. Opening of the valve lltlil has no effect during this operation.

Step seven: Open the start control valve 7l'. Opening of the start control Valve 7l the valve chamber 32 is pressurized through conduits 83 and 8d from the high pressure accumulator d2 which shifts to the spool valve member 7d to the position shown in full lines in FlGURE 7. As soon as port titl is uncovered the valve chamber b2 is pressurized Ifrom port 79. Fluid under pressure in the metering chamber 6d is now in communication with the pump chamber 557 of the engine pump lt) by Way of conduit 9S, port 79, circumferential groove 77, port 73, conduits 99, 59 and 59. `fFluid pressure from the accumulator (i2 in the actuating chamber 69 now urges the meterpiston 67 from its position d' to the position shown in full lines in FGURE 7. The fluid in the metering charnber 6b between the position of the metering piston at 67' to that at 67 is a metered quantity for when the piston 67 has reached its flower limit no further iiuid flow is delivered to the pump chamber 57. Thus the volume displacement of the metering chamber @S should be approximately equal to the displacement of the pump pistons 47 and Sti so that a single charge of iiuid from the metering chamber till is suicient to move the power piston 19 and block member `lll, l2 and i3, through the fuel-air compression stroke and compression-ignition thereof. The engine pump lil thereby makes its initial firing and thus it continues to operate.

After the engine pump 1t) is started it is immaterial whether the spool valve 7.1 is de-energized. However, as a practical matter the start valve 711 becomes dre-energized because when the pump pistons 47 and 59 are moving outboardly (intake stroke) there is a momentary period of low pressure in the conduit 59 which is in communication with the valve chamber 32. This permits the plunger 7dto move rightwardly as viewed in FIGURE 7 and thus the port '78 is closed by the land '75 provided however that the manually operated start control valve 71 is first closed.

The engine pump 1i) is thus running and pumps fluid from the low pressure accumulator 6@ to the high pressure accumulator 62. Since a differential iiuid pressure exists between the high pressure accumulator 62 and the low pressure accumulator 66, this differential fluid pressure is available for performing useful work such as energizing iiuid motors for driving machiney and the like. The iiuid pressue in the low pressure accumulator 6@ should be sufficiently high to prevent cavitation of fluid in the pump chamber 57 at hisher engine speeds.

It will be noted that if the effective mass of the block member and its associated pump piston is equal to the effective mass of the power piston assembly with its associated pump piston, the stroke distance of each relative to the support member 343 will be equal and in opposite direction due to the opposed force reactive relation be tween the two. Thus no vibrational forces are imparted to the support member 34. In order to balance the respective eifective masses, the Ablock member should be made of low density material such as aluminum alloy (except for liner 13) while the power piston assembly should be made of higher density material such as iron or steel.

In the operation of the engine pump 1@ above described the median of the fluid pump chamber 5'/ indicated by the line 1192 (FIGURE 1) may tend to creep in a longitudinal direction with respect to the support member 34 due to uneven wear or diiierences in manufacturing tolerances. In order to maintain the center of the fluid pump chamber 57 on the line 102 so that neither the power piston 19 nor the block member 111, 12 and 13 reach their stroke limiting means with respect to the support means 34, a novel arrangement is shown in FIGURE 6 for accomplishing this purpose.

Referring to FIGURE 6 the uid pump chamber 57 of FIGURE 1 is divided into two chambers, an upper pump chamber 1113 and a lower pump chamber 1M separated by the wall 105 of the iiuid pump cylinder `39. Thus the bore 48 of FIGURE 1 is divided into two longitudinal coaxial bores 106 and 107. The upper pump piston Sii is provided with a truste-conical portion 1118 and the lower pump piston 47 is provided with a frusto-conical portion 1619, both being on the inner ends of their respective pump pistons as shown in FIGURE 6. The fluid inlet to the lower pump chamber `164i is provided by the transverse primary inlet bore 11b communicating with the inlet bore SS. Likewise the uid inlet to the upper pump chamber 103 is provided by the transverse primary inlet bore 111 also communicating with the inlet bore 5S as shown.

In the same transverse plane as that of the bore 111 is a bore 112 which communicates the upper pump chamber 103 with the uid outlet bore 59. Likewise, in the same transverse plane as that of the bore 110 is a bore 113 which communicates the lower pump chamber 104 with the fluid outlet bore 59. At this point it will be observed from FIGURE 6 that the longitudinal distance between bores 111 and 112 from the wall 1115 is equal to the longitudinal distance between the bores 110 and 113 and the wall 105.

The upper pump chamber 103 is also provided with a secondary uid inlet passage 114, communicating with inlet bore 58, having a conventional check valve 115 interposed therein as shown in FIGURE 6. Similarly the lower pump chamber 104 is provided with a secondary fluid inlet passage 116, communicating with inlet bore 5S,

having a conventional check valve 117 interposed therein. It will be noted that the secondary inlet passages 114 and 115 are positioned adjacent to the wall 105 as illustrated in FIGURE 6.

Again referring to FIGURE 6, during operation of the engine pump 1@ if the inbound movement of the lower pump piston t7 becomes excessive due to a shift of the piston and block assemblies to the left for some reason as indicated by the dotted lines, the pump piston 47 progressively throttles fluid How in the bores 11) and 113. This results in a progressive increase in fluid pressure in the lower pump chamber 1614 which in turn increases the resistance to movement of the lower pump piston 47 associated with the block member 11, 12 and 13. Now if the upper pump piston Sib is always the same distance from the wall 1115 as that of the lower pump piston 47 then the fluid pressures in both chambers 103 and 104 will be equal to each other at all times. However in the event that the respective distances of the pump pistons 47' and 55.3 become unequal with respect to the wall 105 then the fluid pressures in the chambers 1% and 104 will become unequal. Since the force driving piston 47 is reactive with the force driving the piston Sil the pump chamber having the higher pressure will cause the other piston to increase its stroke. For example, as shown in FIGURE 6, if the pump piston d'7 moves on its inbound stroke toward the position shown in dotted lines, the pressure in the chamber 1% progressively rises. This progressive rise in pressure in chamber 11M- also progressively increases the resistance to further inbound movement of the pump piston d'7. The progressively increasing resistance to inbound movement of pump piston 47 reects to increase the inbound force of the pump piston 50 as the forces driving pistons 47 and Sti are reactive as previously explained. The increased inbound force thus applied to the piston SQ tends to raise the pressure in chamber 1133 to equal that in the chamber 104. However, there is no 'substantial increase in pressure in the chamber 111.3 until the piston 59 begins to register with the bore 112 whereby iiuid flow therethrough becomes restricted. From this it is evident that progressive restriction of flow through bore 112 correspondingly increases the pressure in chamber 1113 until it is equal to the pressure in chamber 1134 at which time the piston 59 will be substantially the same distance from the wall 1595 as that of piston 47. Thus the midpoint between the pistons 47 and 50 will always coincide approximately with the center of the wall 1135.

During the outbound movement of the pistons 47' and Sti the check valves 115 and 11'7 in the secondary passages 114 and 116 open to permit free access of uid into the chambers 163 and 105 without restriction irrespective of the positions of the pistons 47 and S0. Thus any tendency for the midpoint between the pistons 47 and 50 to shift or creep longitudinally is automatically corrected in the arrangement shown in FIGURE 6.

Having thus described a preferred embodiment of the invention it can now be seen that the objects of the invention have been fully achieved and it must be understood that changes and modifications may be made which do not depart from the spirit of the invention nor from the scope thereof as defined in the appended claims.

What is claimed is:

1. A dynamically balanced single cylinder free piston engine hydraulic pump comprising a stationary support member, a movable power piston assembly including a compressor piston slidably supported on said support member, a fuel combustion chamber positioned in operative relation with respect to said power piston, a movable block member with an air compressor chamber communicatively connected to said fuel combustion chamber and a bounce chamber slidably supported on said support member, said power piston assembly being in slidable relation with said block member, said bounce chamber being capable ot storing energy for moving said power piston in its fuel-air compression stroke,v said combustion chamber having fuel injection means disposed in said block member positioned to energize reciprocally said power piston assembly in opposed force reactive relation with respectto said movable `block member and said bounce chamber, a reciprocable pump means operably connected `to said power piston assembly and said block member, said block member having an effective mass substantially equal to the elfective mass of said power piston assembly for actuating` reciprocally said pump means in dynamic balance with respect to said support member whereby said engine pump is operable to pump Huid without substantial vibrational forces imparted to said support member.

2. A dynamically balanced single cylinder free piston engine hydraulic pump comprising a stationary support member, a movable power piston assembly including a compressor piston slidably supported on said support member, a fuel combustion chamber positioned in operative relation with respect to said power piston, a movable block member `with an air compressor chamber communicatively connected to said fuel combustion chamber i and a bounce chamber slidably supported on said support member, said power piston assembly being in slidable relation with said block` member, said bounce chamber being capable of storing energy for moving said power piston in itsfuel-air compressionstroke, said combustion `chamber having fuel `injection means disposed in said compressor chamber communicatively connected to said fuel combustion chamber, a bounce chamber capable of storing energy for moving said power piston in its fuelair compression stroke, a movable block member including a fuel injector means slidably supported axially on said support member, said power piston assembly being in opposed slidable force reactive relation with respect to said block member and said bounce chamber, an hydraulic pump means disposed longitudinally in said support member drivenly connected in operative relation with said power piston assembly and said block member, said power piston assembly having an effective mass substantially equal to the effective mass of said block member,

,. and combustion means for energizing said engine whereby block member positioned to energize reciprocably said ,c

power piston assembly in opposed force reactive relation with respect to said block member and said bounce chamber, auid pump cylinder disposed on said support member and positioned within said block member, a first fluid pump piston longitudinally disposed slidably in said pump cylinder and drivenly connected to said power piston, a second iluid pump piston longitudinally disposed slidably in said pump cylinder and drivenly connected to said block member, said first pump piston being positioned in opposed relation with respectlo said second pump piston, a pump chamber `disposed in said pump cylinder between said pump pistons, iluid inlet and outlet means disposed in` said support member in communication with said pump chamber, said power piston assembly with said first pumppiston having an effective mass substantially equal to the effective mass of said block member with said second pump piston whereby said engine pump is operable to pump lluid without substantial vibrational forces imparted to said support member.

`3. A dynamically balanced single cylinder free piston engine comprising a stationary support member, a power piston assembly including an air compressor piston axially supported slidably on said support member, `a fuel combustion chamber positioned in operative relation with respect to said power piston, an air compressor chamber communicatively connected to said fuel combustion chamber, a bounce chamber capable of storing energy forrmoving said power piston in its fuel-air compression stroke, a movable block member including a fuel injector means slidablysupported axially on said support member, said power piston assembly being in opposed slidable relation with respect to said block member, energy storing means positioned to move said power piston in its fuel-air compression stroke, said power piston assembly having an effective mass substantially equal to the effective mass of said block member, and combustion means for energizing said engine whereby said piston assembly and said block member reciprocate in opposed relation without substantial vibrational forces imparted to said support member.

4. A dynamically balanced single cylinder free piston engine hydraulic pump comprising a stationary support `member, a power piston assembly including an air compressor piston axially supported slidably on said support member, a fuel combustion chamber positioned in operative relation with respect to said power piston, an air said power piston assembly and block member reciprocate in opposed force reactive relation for actuating said pump means without substantial vibrational forces imparted to said support member.

5. A dynamically balanced single cylinder free piston engine hydraulic pump comprising a stationary support member, a power piston assembly including an air compressor piston supported axially and slidably on said support member, a `movable block member including a fuel injector means slidably supported axially on said support member, said block member having a fuel combustion chamber and a bounce chamber positioned to energize said power piston and block member in operable relation, an air compressor chamber communicatively connected with said combustion chamber, said bounce chamber being capable of storing energ for moving said power piston in its fuel-air compression stroke, said power piston assembly being in opposed slidable force reactive relation with respect to said block member, said support member having a longitudinally disposed bore therein, a lirst pump piston disposed in said bore and operatively `connected in driven relation with said power piston assembly, a second pump piston disposed in said bore and operatively connected in drivenrelation with said block member, said first pump piston being in opposed relation `with respect to said second pump piston forming a pump chamber therebetween in said bore, iiuid inlet and outlet means disposed in said support member communicating with said pump chamber, said power piston assembly with said first pump piston having an effective mass substantially equal to the effective mass of said block member with said second pump piston whereby said engine actuates said pump for pumping said hydraulic luid without substantial vibrational forces imparted to said support member.

6. A dynamically balanced single cylinder free piston engine hydraulic pump comprising a stationary support member, a power piston assembly including an air compressor piston supported axially and slidably on said support member, a movable block member including a fuel `injector means slidably supported axially on said support member, said block member having a fuel combustion chamber and a bounce chamber positioned to energize said power piston assembly and block member in opposed force reactive relation, a compressor chamber communicatively connected to said combustion chamber, a bore disposed longitudinally in said support member, the upper end of said bore extending within said power piston assembly, an upper pump piston disposed in the upper portion of said bore and drivenly connected to said power piston assembly, an elongated slot extending longitudinally disposed in the lower portion of said support member, the upper end of said slot opening into the lower end portion of said bore, said slot having longitudinal walls in transverse spaced relation a distance at least equal to the diameter of said bore, a lower pump piston disposed in the lower portion of said bore and drivenly connected through said slot to said block member, a pump chamber positioned between said pump pistons in said bore, fluid inlet and outlet means disposed in said support member communicatively connected to said pump chamber, said l ll power piston assembly with said upper pump piston having an effective mass substantially equal to the effective mass of said block member with said lower pump piston whereby said engine actuates said pump pistons for pumping hydraulic fluid without substantial vibrational forces imparted to said support member.

7. A dynamically balanced single cylinder free piston engine hydraulic pump comprising a stationary support member, a movable power piston assembly including an air compressor piston slidably supported on said support member, a movable block member with a compressor chamber and a bounce chamber slidably supported in operable relation on said support member, said power piston assembly being in slidable relation with said block member, a fuel combustion chamber having fuel injection means disposed in said block member positioned to energize reciprocably said power piston assembly in opposed relation with respect to said block member, said compressor chamber communicatively connected to said combustion chamber, said bounce chamber being capable of storing energy to move said power piston in its fuel-air compression stroke, a fluid pump cylinder disposed on said support member and positioned within said block member, a first iluid pump piston disposed slidably in said pump cylinder and drivenly connected at its outer end to said power pis-ton assembly, the inner end portion of said first pump piston having a frusto-conical portion tapering inwardly, a second duid pump piston disposed slidably in said pump cylinder and drivenly connected at its outer end to said block member, Lhe inner end portion of said second pump piston having a truste-conical portion tapering inwardly, a rst pump chamber disposed in said pump cylinder adjacent the truste-conical portion of said iirst pump piston, a second pump chamber disposed in said pump cylinder adjacent the frusto-conical portion of said second pump piston, said second pump chamber being independent of said iirst pump chamber, fluid inlet passages disposed in said pump cylinder communicatively connected to said pump chambers, Huid outlet passages disposed in said pump cylinder communicatively connected to each of said pump chambers, said outlet passages being positioned registcrably with said pump pistons in fluid throttling relation for limiting the inbound movement of each of said pump pistons independently of each other, said power piston assembly with said iirst pump piston having an effective mass substantially equal to the elfective mass of said block member with said second piston whereby said engine pump is operable to pump fluid from said inlet passages to said outlet passages without substantial vibrational forces imparted to said support member.

8. A dynamically balanced single cylinder free piston engine hydraulic pump comprising a stationary support member, a power piston assembly including an air compressor piston axially supported slidably on said support member, a movable block member including a fuel injector means and a combustion chamber slidably supported axially on said support member, said power piston assembly being in opposed slidable force reactive relation with respect to said block member, means capable of storing energy to move said power piston in its fuel-air compression stroke, an hydraulic pump means disposed longitudinally in said support member drivenly connected in operative relation with said power piston assembly and said block member, iiuid throttling means disposed in said hydraulic pump for limiting inbound movement of said power piston assembly and said movable block member, said power piston assembly having an effective mass substantially equal to the effective mass of said block member, and an air compressor chamber communicatively connected with said combustion chamber, said power piston assembly and block member are energized to reciprecate in opposed force reactive relation for actuating said pump means without substantial vibrational forces imparted to said support member.

9. A dynamically balanced single cylinder free piston engine hydraulic pump comprising a stationary support member, a power piston assembly including an air compressor piston supported axially and slidably on said support member, a movable block member including a fuel injector means slidably supported axially on said support member, said block member having a fuel combustion chamber and a bounce chamber positioned to energize said power piston and block member, an air compressor chamber communicatively connected to said combustion chamber, said power piston assembly being in opposed slidable force reactive relation with respect to said block member, a longitudinally disposed first bore in said support member opening into said power piston assembly, a longitudinally disposed second bore in said support member opening into the atmosphere, a rst fluid pump piston disposed slidably in said lirst bore and drivenly connected at its outer end to said power piston assembly, a second fluid pump piston disposed slidably in said second bore and drivenly connected at its outer end to said lock member, a lirst pump chamber disposed in said iirst bore adjacent the inner end of said lirst pump piston, a second pump chamber disposed in said second bore adjacent the inner end of said second pump piston, said second pump chamber being independent of said first pump chamber, fluid inlet passages disposed in said support member communicatively connected to said pump chambers, fluid outlet passages disposed in said support member communicatively connected to said pump chambers, said outlet passages being positioned registerably with said pump pistons in fluid throttling relation for limiting the inbound movement of eachvof said pump pistons independently of each other, said-power piston assembly with said iirst pump piston having an effective mass substantially equal to the effective mass of said block member with said second pump piston whereby said engine actuates said pump pistons for pumping hydraulic iiuid without substantial vibrational forces imparted to said support member.

References Cited in the file of this patent UNITED STATES PATENTS 1,331,504 Hewitt Feb. 24, 1920 2,168,828 Pescara Aug. 8, 1939 2,215,326 Janickc Sept. 17, 1940 2,652,781 Deardorif et al Sept. 22, 1953 2,949,858 Costley Aug. 23, 1960 FOREGN PATENTS 715,748 France Sept. 29, 1931 

1. A DYNAMICALLY BALANCED SINGLE CYLINDER FREE PISTON ENGINE HYDRAULIC PUMP COMPRISING A STATIONARY SUPPORT MEMBER, A MOVABLE POWER PISTON ASSEMBLY INCLUDING A COMPRESSOR PISTON SLIDABLY SUPPORTED ON SAID SUPPORT MEMBER, A FUEL COMBUSTION CHAMBER POSITIONED IN OPERATIVE RELATION WITH RESPECT TO SAID POWER PISTON, A MOVABLE BLOCK MEMBER WITH AN AIR COMPRESSOR CHAMBER COMMUNICATIVELY CONNECTED TO SAID FUEL COMBUSTION CHAMBER AND A BOUNCE CHAMBER SLIDABLY SUPPORTED ON SAID SUPPORT MEMBER, SAID POWER PISTON ASSEMBLY BEING IN SLIDABLE RELATION WITH SAID BLOCK MEMBER, SAID BOUNCE CHAMBER BEING CAPABLE OF STORING ENERGY FOR MOVING SAID POWER PISTON IN ITS FUEL-AIR COMPRESSION STROKE, SAID COMBUSTION CHAMBER HAVING FUEL INJECTION MEANS DISPOSED IN SAID BLOCK MEMBER POSITIONED TO ENERGIZE RECIPROCALLY SAID POWER PISTON ASSEMBLY IN OPPOSED FORCE REACTIVE RELATION WITH RESPECT TO SAID MOVABLE BLOCK MEMBER AND SAID BOUNCE CHAMBER, A RECIPROCABLE PUMP MEANS OPERABLY CONNECTED TO SAID POWER PISTON ASSEMBLY AND SAID BLOCK MEMBER, SAID BLOCK MEMBER HAVING AN EFFECTIVE MASS SUBSTANTIALLY EQUAL TO THE EFFECTIVE MASS OF SAID POWER PISTON ASSEMBLY FOR ACTUATING RECIPROCALLY SAID PUMP MEANS IN DYNAMIC BALANCE WITH RESPECT TO SAID SUPPORT MEMBER WHEREBY SAID ENGINE PUMP IS OPERABLE TO PUMP FLUID WITHOUT SUBSTANTIAL VIBRATIONAL FORCES IMPARTED TO SAID SUPPORT MEMBER. 